Impact of HMME-PDT on Pg of the surface of implants and cementum tablets

Abstract

Objective To evaluate the bactericidal effect of diode laser on Porphyromonas gingivalis (Pg),and to explore an optimized protocol for a safe dose of photodynamic therapy (PDT) to eliminate periodontal pathogens as well as the impact on the implant surfaces,so as to provide theoretical and experimental basis for PDT in periimplantitis therapy.Methods Artificial in vitro models were formatted by culturing Pg standard strain and ITI (International Team for Implantology) implants together in CDC broth.Then artificial in vitro models were treated by different doses of hematoporphyrin monomethyl ether (HMME) and different energy density of laser (EDL) for 60 s.The cultures were counted by colony form unit (CFU),and SPSS 17.0 statistical software was used for data statistical analysis to select the best EDL and HMME dose.Finally,ITI implants were observed by scanning electron microscope (SEM) to evaluate the impact of HMME-PDT on Pg of implant surfaces.Results When EDL was 12 J/cm2 and mass concentration of HMME was 25 μg/ml,SEM observations showed that PDT could effectively kill Pg ((13.00±5.00) CFU)without damaging the implant surfaces.Conclusions PDT therapy combining 630 nm diode laser with photosensitizer HMME have good bactericidal effect on Pg,and the EDL and HMME dose is as small as the clinical applicable safe dose. Key words: Photodynamic therapy; Diode laser; , Hematoporphyrin monomethyl ether; Porphyromonas gingivalis; Peri-implantitis